{"id":349,"date":"2026-09-18T09:18:29","date_gmt":"2026-09-18T09:18:29","guid":{"rendered":"https:\/\/fenggu-bio.com\/vhp-concentration-humidity-condensation\/"},"modified":"2026-09-18T09:18:29","modified_gmt":"2026-09-18T09:18:29","slug":"vhp-concentration-humidity-condensation","status":"publish","type":"post","link":"https:\/\/fenggu-bio.com\/ru\/vhp-concentration-humidity-condensation\/","title":{"rendered":"\u041f\u0430\u0440\u0430\u043c\u0435\u0442\u0440\u044b \u0446\u0438\u043a\u043b\u0430 VHP: \u041a\u043e\u043d\u0446\u0435\u043d\u0442\u0440\u0430\u0446\u0438\u044f, \u0432\u043b\u0430\u0436\u043d\u043e\u0441\u0442\u044c, \u043d\u0430\u0441\u044b\u0449\u0435\u043d\u0438\u0435 \u0438 \u043a\u043e\u043d\u0434\u0435\u043d\u0441\u0430\u0446\u0438\u044f"},"content":{"rendered":"<style>\n.entry-title,.ast-single-post .entry-header{display:none!important}\n.fg-art{font-family:-apple-system,BlinkMacSystemFont,\"Segoe UI\",Roboto,\"Helvetica Neue\",Arial,sans-serif;color:#1e2838;line-height:1.72;max-width:820px;margin:0 auto;padding:0 22px;font-size:16.5px}\n.fg-art .fg-eyebrow{display:inline-block;background:#e3ecfa;color:#003AA1;font-weight:700;font-size:12px;letter-spacing:.7px;padding:5px 13px;border-radius:20px;text-transform:uppercase;margin:34px 0 14px}\n.fg-art h1{font-size:32px;line-height:1.22;color:#002B78;margin:0 0 12px;font-weight:800}\n.fg-art .meta{font-size:13.5px;color:#7a8699;margin:0 0 26px;border-bottom:1px solid #e6ebf3;padding-bottom:18px}\n.fg-art h2{font-size:23px;color:#002B78;margin:38px 0 12px;line-height:1.28}\n.fg-art h3{font-size:18px;color:#003AA1;margin:22px 0 8px}\n.fg-art p{margin:0 0 16px}\n.fg-art .lead{font-size:18px;color:#3a4658}\n.fg-art figure{margin:26px 0}\n.fg-art img{width:100%;border-radius:12px;box-shadow:0 6px 22px rgba(0,58,161,.12);display:block}\n.fg-art figcaption{font-size:13px;color:#7a8699;margin-top:9px;text-align:center}\n.fg-art table{border-collapse:collapse;width:100%;margin:22px 0;font-size:14.5px}\n.fg-art th,.fg-art td{border:1px solid #d7dfea;padding:11px 14px;text-align:left;vertical-align:top}\n.fg-art thead th{background:#002B78;color:#fff;font-weight:700}\n.fg-art tbody th{background:#eff4fb;color:#002B78;font-weight:700;width:20%}\n.fg-art tbody tr:nth-child(even) td{background:#f7f9fc}\n.fg-art ul{margin:0 0 16px;padding-left:22px}.fg-art li{margin:7px 0}\n.fg-art .fg-cta{background:linear-gradient(120deg,#002B78,#003AA1);color:#fff;border-radius:14px;padding:30px 28px;margin:38px 0 10px;text-align:center}\n.fg-art .fg-cta h3{color:#fff;font-size:22px;margin:0 0 8px}\n.fg-art .fg-cta p{color:#dce7f7;margin:0 0 18px;font-size:15.5px}\n.fg-art .fg-btn{display:inline-block;background:#EC001B;color:#fff;padding:13px 28px;border-radius:6px;font-weight:600;font-size:15.5px;text-decoration:none;margin:0 6px 8px}\n.fg-art .fg-btn.o{background:transparent;border:2px solid rgba(255,255,255,.7)}\n.fg-art a{color:#003AA1;text-decoration:underline}\n.fg-art .fg-cta a{text-decoration:none;color:#fff}\n@media(max-width:640px){.fg-art h1{font-size:26px}.fg-art th,.fg-art td{padding:9px 10px;font-size:13.5px}}\n<\/style>\n<article class=\"fg-art\">\n<span class=\"fg-eyebrow\">VHP Cycle &middot; Parameters<\/span><\/p>\n<h1>VHP Cycle Parameters: Concentration, Humidity, Saturation &amp; Condensation<\/h1>\n<div class=\"meta\">\u041f\u043e \u043c\u0430\u0442\u0435\u0440\u0438\u0430\u043b\u0430\u043c Fenggu Medical Equipment \u00b7 \u0424\u0438\u0437\u0438\u043e\u043b\u043e\u0433\u0438\u0447\u0435\u0441\u043a\u0430\u044f \u0441\u0442\u0435\u0440\u0438\u043b\u0438\u0437\u0430\u0446\u0438\u044f \u0438 \u043a\u043e\u043d\u0442\u0440\u043e\u043b\u044c \u0437\u0430\u0433\u0440\u044f\u0437\u043d\u0435\u043d\u0438\u044f<\/div>\n<p class=\"lead\">Whether a VHP (vaporized hydrogen peroxide) cycle actually works &mdash; and whether it corrodes your equipment or fails to aerate &mdash; comes down to four interacting parameters: <strong>H&#8322;O&#8322; concentration, humidity, relative saturation (RS) and temperature<\/strong>. Set them wrong and you get condensation, uneven kill, prolonged aeration, or corroded chambers. This guide explains how the parameters trade off, the RH-vs-RS distinction that trips people up, and how to keep a cycle just below the condensation line.<\/p>\n<figure>\n<img width=\"669\" height=\"858\" decoding=\"async\" src=\"\/wp-content\/uploads\/site\/airlock-vhp-sterilization-03.jpg\" alt=\"Fenggu VHP biodecontamination system \u2014 cycle parameters (H2O2 concentration, humidity, relative saturation, temperature) controlled to stay below the condensation point\"><figcaption>A VHP cycle is a balancing act: enough peroxide vapour to kill spores, but never so much that the chamber crosses into condensation.<\/figcaption><\/figure>\n<h2>The whole game: staying just below condensation<\/h2>\n<p>35% hydrogen peroxide boils at about 108&nbsp;&deg;C, so at the 20&ndash;30&nbsp;&deg;C of a real isolator or cleanroom the peroxide is below its evaporation point &mdash; yet a usable amount of <strong>vapour-phase H&#8322;O&#8322;<\/strong> still exists, constantly forming and decomposing. That is why a VHP cycle must <strong>continuously top up<\/strong> the vapour to hold the target concentration. The catch: push the vapour too high and the chamber crosses its saturation point and <strong>condenses<\/strong> &mdash; which corrodes surfaces and sensors, prolongs aeration, and makes the kill uneven. The entire art of a VHP cycle is holding the sweet spot: <em>enough<\/em> vapour to be sporicidal, but <em>just below<\/em> the condensation line.<\/p>\n<h2>RH vs RS &mdash; the distinction that trips people up<\/h2>\n<p>People assume gassing raises the humidity. It mostly doesn&#8217;t &mdash; and confusing the two terms is where cycles go wrong:<\/p>\n<ul>\n<li><strong>Relative humidity (RH)<\/strong> is how much <em>water<\/em> vapour the air holds versus its saturation point at that temperature.<\/li>\n<li><strong>Relative saturation (RS)<\/strong> is how much <em>water plus hydrogen peroxide<\/em> vapour the air holds versus saturation.<\/li>\n<\/ul>\n<p>During the gassing phase you are adding H&#8322;O&#8322; vapour, so it is the <strong>RS that climbs<\/strong> toward 100%, while RH stays roughly flat. Condensation happens at <strong>RS&nbsp;100%<\/strong>, not RH 100%. This is exactly why the cycle starts with a <strong>dehumidification \/ conditioning<\/strong> phase: lowering the water vapour first leaves more headroom to inject H&#8322;O&#8322; vapour before hitting RS&nbsp;100%. Monitor and control RS, not RH.<\/p>\n<h2>The concentration&ndash;humidity trade-off<\/h2>\n<p>Concentration and humidity trade against each other. A <strong>low<\/strong> H&#8322;O&#8322; concentration needs a <strong>\u0432\u044b\u0448\u0435<\/strong> humidity to kill well; a <strong>high<\/strong> concentration works at <strong>\u043d\u0438\u0436\u0435<\/strong> humidity. So the common, economical operating regimes are:<\/p>\n<table>\n<thead>\n<tr>\n<th>\u0420\u0435\u0436\u0438\u043c<\/th>\n<th>H&#8322;O&#8322; concentration<\/th>\n<th>Humidity<\/th>\n<th>Character<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<th>Dry<\/th>\n<td>High (~800&nbsp;ppm)<\/td>\n<td>\u041d\u0438\u0437\u043a\u0438\u0439<\/td>\n<td>No condensation; material-friendly; longer aeration of high peroxide.<\/td>\n<\/tr>\n<tr>\n<th>Balanced<\/th>\n<td>Medium (~600&nbsp;ppm)<\/td>\n<td>\u0421\u0440\u0435\u0434\u043d\u0438\u0439<\/td>\n<td>The usual choice for isolators &mdash; easy to control in a small volume.<\/td>\n<\/tr>\n<tr>\n<th>Wet<\/th>\n<td>Low (~400&nbsp;ppm)<\/td>\n<td>\u0412\u044b\u0441\u043e\u043a\u0438\u0439<\/td>\n<td>Micro-condensation aids kill; slower but efficient; gentler on walls.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>All three regimes live <strong>below the condensation line<\/strong> (RS&nbsp;100%). The more water vapour you carry, the less peroxide vapour you can add before condensing &mdash; so the safe operating window slopes down:<\/p>\n<figure>\n<svg viewbox=\"0 0 640 320\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" style=\"width:100%;height:auto;background:#fff;border-radius:12px;box-shadow:0 6px 22px rgba(0,58,161,.12);padding:12px 0\" role=\"img\" aria-label=\"VHP operating window: H2O2 concentration on the vertical axis, humidity on the horizontal; a downward-sloping condensation line (RS 100%) with a safe zone below holding three operating points: dry high-concentration, balanced, and wet low-concentration\">\n<defs><marker id=\"pa\" markerwidth=\"9\" markerheight=\"9\" refx=\"4\" refy=\"3\" orient=\"auto\"><path d=\"M0 0 L8 3 L0 6 z\" fill=\"#7a8699\"\/><\/marker><\/defs>\n<!-- axes -->\n<line x1=\"70\" y1=\"270\" x2=\"600\" y2=\"270\" stroke=\"#7a8699\" stroke-width=\"1.6\" marker-end=\"url(#pa)\"\/>\n<line x1=\"70\" y1=\"270\" x2=\"70\" y2=\"30\" stroke=\"#7a8699\" stroke-width=\"1.6\" marker-end=\"url(#pa)\"\/>\n<text x=\"335\" y=\"300\" text-anchor=\"middle\" font-size=\"12.5\" fill=\"#5a6472\">Humidity \/ water vapour &rarr;<\/text>\n<text x=\"26\" y=\"150\" text-anchor=\"middle\" font-size=\"12.5\" fill=\"#5a6472\" transform=\"rotate(-90 26 150)\">H&#8322;O&#8322; concentration &rarr;<\/text>\n<!-- condensation line (down-sloping) -->\n<line x1=\"90\" y1=\"70\" x2=\"580\" y2=\"250\" stroke=\"#c1521f\" stroke-width=\"2.4\" stroke-dasharray=\"7 5\"\/>\n<text x=\"470\" y=\"150\" font-size=\"12.5\" font-weight=\"700\" fill=\"#c1521f\" transform=\"rotate(20 470 150)\">Condensation line (RS 100%)<\/text>\n<!-- danger zone label above line -->\n<text x=\"300\" y=\"60\" text-anchor=\"middle\" font-size=\"12\" fill=\"#c1521f\">above the line &rarr; condensation (corrosion, uneven kill, long aeration)<\/text>\n<!-- safe zone -->\n<path d=\"M70 270 L70 90 L575 262 L70 270 Z\" fill=\"#e9f6ee\" opacity=\"0.7\"\/>\n<text x=\"230\" y=\"245\" text-anchor=\"middle\" font-size=\"12.5\" font-weight=\"700\" fill=\"#1f7a44\">Safe operating window<\/text>\n<!-- points -->\n<circle cx=\"150\" cy=\"120\" r=\"7\" fill=\"#002B78\"\/><text x=\"162\" y=\"118\" font-size=\"12\" font-weight=\"700\" fill=\"#002B78\">Dry &middot; ~800 ppm \/ low RH<\/text>\n<circle cx=\"270\" cy=\"175\" r=\"7\" fill=\"#003AA1\"\/><text x=\"282\" y=\"173\" font-size=\"12\" font-weight=\"700\" fill=\"#003AA1\">Balanced &middot; ~600 ppm \/ mid RH<\/text>\n<circle cx=\"400\" cy=\"228\" r=\"7\" fill=\"#2e6b46\"\/><text x=\"412\" y=\"226\" font-size=\"12\" font-weight=\"700\" fill=\"#2e6b46\">Wet &middot; ~400 ppm \/ high RH<\/text>\n<\/svg><figcaption>The VHP operating window: as humidity rises, the peroxide concentration you can hold before condensing falls. All working cycles sit in the safe zone below the RS-100% line. Values are indicative. (Original Fenggu schematic.)<\/figcaption><\/figure>\n<h2>Dry or wet: isolator vs room<\/h2>\n<p>The regime you pick follows the space:<\/p>\n<ul>\n<li><strong>Isolators and small chambers &rarr; balanced (mid concentration, mid humidity).<\/strong> A small, sealed volume is easy to control, and going to very high concentration just makes aeration back down to &le;1&nbsp;ppm take longer. Dry-leaning cycles also protect the electronics, coatings and seals inside.<\/li>\n<li><strong>Rooms and large spaces &rarr; wet (low concentration, high humidity).<\/strong> Large volumes are pre-conditioned to ~40&ndash;60% RH before gassing; a low-concentration, higher-saturation cycle kills well, is gentler on wall coatings, and an overnight cycle-plus-aeration is perfectly workable. At the same concentration (say 180&nbsp;ppm), a <strong>higher saturation gives a better kill<\/strong>.<\/li>\n<\/ul>\n<p>For the dry-vs-wet definitions in the context of validation, and why RS is a critical process parameter, see <a href=\"\/ru\/vhp-cycle-development-qualification\/\">\u0420\u0430\u0437\u0440\u0430\u0431\u043e\u0442\u043a\u0430 \u0438 \u043a\u0432\u0430\u043b\u0438\u0444\u0438\u043a\u0430\u0446\u0438\u044f \u0432 \u0441\u0444\u0435\u0440\u0435 \u0432\u0435\u043b\u043e\u0441\u0438\u043f\u0435\u0434\u043d\u043e\u0433\u043e \u0441\u043f\u043e\u0440\u0442\u0430 VHP<\/a>.<\/p>\n<figure>\n<img width=\"1600\" height=\"1219\" decoding=\"async\" src=\"\/wp-content\/uploads\/site\/hvac-02.jpg\" alt=\"Fenggu HVAC-integrated VHP system pre-conditioning a cleanroom to 40-60% RH before gassing for a low-concentration, high-saturation room decontamination cycle\"><figcaption>For whole rooms, the space is pre-conditioned before gassing &mdash; a low-concentration, higher-saturation cycle that is gentle on wall coatings.<\/figcaption><\/figure>\n<h2>Condensation: friend and enemy<\/h2>\n<p>A little condensation is not automatically bad. Research shows <strong>micro-condensation<\/strong> &mdash; sub-micron, invisible to the eye &mdash; is part of the kill in a wet cycle; because water condenses before peroxide, the condensed film is far more concentrated than the liquid solution. But <strong>over<\/strong>-condensation is the enemy: it corrodes chambers and sensors, drags out the aeration phase, and makes the kill inconsistent across the load. The rule is to keep the vapour <strong>unsaturated, or only near-saturated<\/strong> &mdash; never in visible condensation. In practice, saturation is harder to hold than the plan suggests: a room cycle that targets 40&ndash;60% can easily spike to 80&ndash;90% saturation, which is exactly why RS must be logged and controlled throughout.<\/p>\n<h2>What this means for BI placement and monitoring<\/h2>\n<p>Because VHP is a <strong>surface<\/strong> process with limited penetration, biological indicators are placed where vapour struggles to reach or where it is coldest &mdash; room corners, near return-air ducts, the farthest points from injection, the core zone, and at representative heights. Flooding a chamber with dozens of BIs adds little; a risk-based set at the true worst-case points is what proves the cycle. Log <strong>temperature, RH, H&#8322;O&#8322; concentration (ppm) and RS<\/strong> throughout, and confirm the end-point by aerating to <strong>&le;1&nbsp;ppm<\/strong>. Cycles are validated with the peroxide-resistant biological indicator <em>\u0413\u0435\u043b\u0430\u0431\u0438\u043e\u0441\u0442\u0430\u0441 \u0441\u0442\u0435\u0430\u0440\u043e\u0442\u0435\u0440\u043c\u043e\u0444\u0438\u043b\u0443\u0441<\/em> in an overkill approach &mdash; see <a href=\"\/ru\/vhp-validation-biological-indicators\/\">\u041a\u0430\u043a \u043f\u043e\u0434\u0442\u0432\u0435\u0440\u0436\u0434\u0430\u0435\u0442\u0441\u044f \u0446\u0438\u043a\u043b VHP<\/a>.<\/p>\n<h2>\u0427\u0430\u0441\u0442\u043e \u0437\u0430\u0434\u0430\u0432\u0430\u0435\u043c\u044b\u0435 \u0432\u043e\u043f\u0440\u043e\u0441\u044b<\/h2>\n<p><strong>Should I control RH or RS?<\/strong><br \/>RS. Condensation is governed by relative saturation (water + peroxide vapour), which rises during gassing while RH stays roughly flat. Controlling RH alone will let you condense unexpectedly.<\/p>\n<p><strong>Higher concentration is always better, right?<\/strong><br \/>No. Higher concentration means longer aeration and more corrosion risk. In a small isolator a balanced mid-concentration cycle is usually the most practical; rooms often do better on low concentration and higher saturation.<\/p>\n<p><strong>Why does my room cycle take so long?<\/strong><br \/>Usually aeration &mdash; high peroxide or over-condensation (absorbed by seals, cellulose, coatings) takes a long time to break down to &le;1&nbsp;ppm. Lower the concentration, avoid condensation, and check for absorbent materials in the load.<\/p>\n<div class=\"fg-cta\">\n<h3>Dialling in a VHP cycle?<\/h3>\n<p>Tell us your enclosure or room volume and target grade, and our engineers will set a validatable VHP cycle &mdash; concentration, humidity and saturation tuned to kill reliably and aerate fast, without condensation.<\/p>\n<p><a class=\"fg-btn\" href=\"\/ru\/products\/hvac-integrated-vhp-system\/\">View VHP Systems<\/a><br \/>\n<a class=\"fg-btn o\" href=\"\/ru\/contact\/\">\u041f\u043e\u0433\u043e\u0432\u043e\u0440\u0438\u0442\u0435 \u0441 \u0438\u043d\u0436\u0435\u043d\u0435\u0440\u043e\u043c<\/a>\n<\/div>\n<\/article>","protected":false},"excerpt":{"rendered":"<p>VHP Cycle &middot; Parameters VHP Cycle Parameters: Concentration, Humidity, Saturation &amp; Condensation By Fenggu Medical Equipment &middot; Pharmaceutical Sterilization &amp; [&hellip;]<\/p>\n","protected":false},"author":0,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[1],"tags":[],"class_list":["post-349","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/fenggu-bio.com\/ru\/wp-json\/wp\/v2\/posts\/349","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/fenggu-bio.com\/ru\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/fenggu-bio.com\/ru\/wp-json\/wp\/v2\/types\/post"}],"replies":[{"embeddable":true,"href":"https:\/\/fenggu-bio.com\/ru\/wp-json\/wp\/v2\/comments?post=349"}],"version-history":[{"count":0,"href":"https:\/\/fenggu-bio.com\/ru\/wp-json\/wp\/v2\/posts\/349\/revisions"}],"wp:attachment":[{"href":"https:\/\/fenggu-bio.com\/ru\/wp-json\/wp\/v2\/media?parent=349"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/fenggu-bio.com\/ru\/wp-json\/wp\/v2\/categories?post=349"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/fenggu-bio.com\/ru\/wp-json\/wp\/v2\/tags?post=349"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}